Based on the implementation of school-wide positive behavior supports (SWPBS) in high schools, the current study examined the effect of supporting buy-in through conducting needs assessments and focused professional development for high school staff when implementing SWPBS. The effectiveness of the two additional items was investigated using two treatment schools and two comparison schools. The hypothesis was that schools with enhanced support would implement SWPBS better and student office discipline referrals (ODRs) would drop due to the better implementation. Overall, the results showed the treatment schools improved in fidelity and demonstrated significant improvement in numbers of ODRs. In contrast, both comparison schools decreased in fidelity and none demonstrated significant changes in ODRs. Suggestions for practice and future research are provided.